Fertilizer & Nutrient Calculator

Don't over-apply. Enter your lawn's square footage and the analysis from your fertilizer bag to find the perfect amount of product for a healthy, green space.

Total Area (sq ft)*

Nitrogen % (N) on bag*

Target Rate (lb N per 1000 sq ft)

Weight of one bag (lb)

Total Product (lb) = [(Area / 1000) × Target Rate] / (N% / 100)

Scenario: You have a 5,000 sq ft lawn and a bag of 20-0-0 fertilizer. You want to apply 1 lb of N per 1,000 sq ft. Calculation: 1. Target N: (5000 / 1000) * 1 = 5 lbs N. 2. Total Product: 5 / 0.20 = 25 lbs. 3. If bag is 25 lbs, you need exactly 1 bag. Result: 1 bag required.

What do the numbers on a fertilizer bag mean (N-P-K)?

The three numbers represent the percentage by weight of Nitrogen (N), Phosphorus (P), and Potassium (K) in the bag. For example, a 10-10-10 bag contains 10% of each nutrient.

How much nitrogen does my lawn need?

A standard recommendation for most lawns is 1 pound of nitrogen per 1,000 square feet per application. Always perform a soil test for specific needs.

How do I calculate how many bags I need?

First, find the pounds of fertilizer needed for your area. Then, divide that by the weight of one bag. For example, if you need 50 lbs of fertilizer and bags are 25 lbs each, you need 2 bags.

Can I apply too much fertilizer?

Yes. Over-fertilizing can cause "fertilizer burn" (salt damage to grass), lead to excessive leaf growth at the expense of roots, and cause environmental runoff into local waterways.

🔗 Related Calculators

📐 Formula

Total Product (lb) = [(Area / 1000) × Target Rate] / (N% / 100)

📝 Example Calculation

❓ Frequently Asked Questions

What do the numbers on a fertilizer bag mean (N-P-K)?▼

The three numbers represent the percentage by weight of Nitrogen (N), Phosphorus (P), and Potassium (K) in the bag. For example, a 10-10-10 bag contains 10% of each nutrient.

How much nitrogen does my lawn need?▼

A standard recommendation for most lawns is 1 pound of nitrogen per 1,000 square feet per application. Always perform a soil test for specific needs.

How do I calculate how many bags I need?▼

First, find the pounds of fertilizer needed for your area. Then, divide that by the weight of one bag. For example, if you need 50 lbs of fertilizer and bags are 25 lbs each, you need 2 bags.

Can I apply too much fertilizer?▼

Yes. Over-fertilizing can cause "fertilizer burn" (salt damage to grass), lead to excessive leaf growth at the expense of roots, and cause environmental runoff into local waterways.